1. Field
The present disclosure relates to a PCV valve apparatus.
2. Description of the Related Art
When an engine is in operation, unburned gas leaks through the gap between the piston and the cylinder to the crank case, and becomes gas containing moisture, oil mist, and so forth in the crank case, that is, so-called “blow-by gas” is generated. Releasing this blow-by gas directly into the atmosphere causes air pollution. So, an engine is provided with a positive crankcase ventilation (PCV) apparatus for separating oil mist and so forth from blow-by gas, then returning the blow-by gas to the intake system, sending the blow-by gas into the combustion chamber, and burning the blow-by gas. The release of blow-by gas into the atmosphere is thereby suppressed.
The PCV apparatus includes a PCV valve apparatus and a PCV pipe. The PCV valve apparatus is attached to an engine main body (for example, a cylinder head cover), and regulates the amount of blow-by gas returned to the intake system using intake negative pressure. The PCV pipe is connected to the downstream end of the PCV valve apparatus, and connects the PCV valve apparatus and the intake system. The PCV pipe has a function of leading blow-by gas led out from the PCV valve apparatus to the intake system. The intake system is provided with a flow rate sensor that detects the flow rate of fluid flowing through the intake system.